1. Field of the Invention
The present invention relates generally to linear, curved or rotary electric machines and, more particularly, to an electric machine which includes first and second movers which are adjacent to each other and have a phase angle difference of 60° therebetween, wherein when the first mover includes phases U, V and W and the second mover includes phases /U, /V and /W, pulsations of thrust caused by end effect can be mitigated, and when a stator comprises an iron core having permanent magnets and salient poles which alternate with each other, the number of permanent magnets can be reduced to half of that of a conventional linear electric machine.
2. Description of the Related Art
Generally, linear electric machines have been widely used for precision position control. A permanent magnet linear synchronous motor is a representative example of such conventional linear electric machines. Typically, in a conventional permanent magnet linear synchronous motor, a mover includes an iron core and three-phase coils, and a stator includes an iron core and permanent magnets. Therefore, as the distance that the mover moves is increased, the number of permanent magnets used is increased, resulting in an increase in the production cost. In addition, due to end effect induced on an entry end and an exit end of the mover, there is pulsation of thrust and normal force.